Observing System Startup andPerforming a Basic Configuration 4-35
Performing Other Configuration Tasks
Table4-4 specifies the content of the boot field, which defines a source for booting the default Cisco IOS software image required to run the router. The content of the boot field is specified as a binary number.
Table4-4 Definition of Bits in Boot Field of Software Configuration Register
11 and 12 0x0800 to 0x1000 Defines the console baud rate (the default setting is
9600 baud).
13 0x2000 Boots the default Flash memory software if the
network boot fails.
14 0x4000 IP broadcasts do not have network numbers.
15 0x8000 Enables diagnostic messages and ignores the
contents of NVRAM.
1. OEM stands for original equipment manufacturer.
Boot Field Bits Meaning
00 On power up, the system remains at the ROM monitor prompt (rommon>),
awaiting a user command to boot the system manually.
01 On power up, the system automatically boots the first system image found in
the onboard Flash memory single inline memory module (SIMM) on the RP.
02 to 0F On power up, the system boots automatically from a default Cisco IOS
software image stored on a TFTP server in the network. For this setting, it is
assumed that the Ethernet port on the RP is configured and operational. A
default Cisco IOS software image is typically kept on a Cisco “Help Desk”
server in the network for ready access by anyone needing a boot image. This
setting also enables boot system commands that override the default
filename.
Table4-3 Definition of Bits in the Software Configuration Register (Continued)
Bit Number Hexadecimal Value Meaning/Function